Symmetric and irregular shaped plasmas using modular microwave sources

ABSTRACT

Embodiments include a plasma processing tool that includes a processing chamber, and a plurality of modular microwave sources coupled to the processing chamber. In an embodiment, the plurality of modular microwave sources include an array of applicators that are positioned over a dielectric body that forms a portion of an outer wall of the processing chamber. The array of applicators may be coupled to the dielectric body. Additionally, the plurality of modular microwave sources may include an array of microwave amplification modules. In an embodiment, each microwave amplification module may be coupled to at least one of the applicators in the array of applicators. According to an embodiment, the dielectric body be planar, non-planar, symmetric, or non-symmetric. In yet another embodiment, the dielectric body may include a plurality of recesses. In such an embodiment, at least one applicator may be positioned in at least one of the recesses.

BACKGROUND 1) Field

Embodiments relate to the field of microwave plasma sources and, inparticular, to the formation of symmetric and/or irregular shapedplasmas using modular microwave plasma sources.

2) Description of Related Art

Plasma processing is used extensively in the manufacture of manydifferent technologies, such as those in the semiconductor industry,display technologies, microelectromechanical systems (MEMS), and thelike. Currently, radio frequency (RF) generated plasmas are most oftenused. However, plasmas generated with a microwave source allow fordenser plasmas and/or plasmas with a high concentration of excitedneutral species. Unfortunately, plasmas generated with a microwavesource also suffer their own drawbacks.

Typical microwave plasma systems use a singular, large source ofmicrowave radiation (typically a magnetron) and a transmission path forguiding the microwave radiation from the magnetron to the processingchamber. For typical high power applications in the semiconductorindustry, the transmission path is a microwave waveguide. Waveguides areused because outside of a waveguide designed to carry the specificfrequency of the microwave source, the microwave power attenuatesrapidly with distance. Additional components, such as tuners, couplers,mode transformers, and the like are also required to transmit themicrowave radiation to the processing chamber. These components limitthe construction to large systems (i.e., at least as large as the sum ofthe waveguide and associated components), and severely limit the design.As such the geometry of the plasma that may be produced is constrainedsince the geometry of the plasma resembles the shape of the waveguides.

In such microwave sources, the size of the microwave plasma source islimited to a dimensions that is equal to or larger than half the wavelength (i.e., λ/2) of the microwave radiation. The dimensions of themicrowave plasma sources can only be in multiples of a half wavelength(i.e., Nλ/2, where N is equal to any positive integer) of the microwaveradiation to produce a stable microwave plasma. At 2.45 GHz, thewavelength of the microwave is at 12.25 cm in air or vacuum. As such,the dimension of the plasma has to be in multiples of 6.125 cm.Accordingly, the microwave plasma sources are limited to certainsymmetrical geometric shape and sizes, and limits where a microwaveplasma sources may be used.

Accordingly, it is difficult to match the geometry of the plasma to thegeometry of the substrate that is being processed. In particular, it isdifficult to create a microwave plasma where the plasma is generatedover the entire surface of the wafer of larger substrates (e.g., 300 mmor greater wafers). Some microwave generated plasmas may use a slot lineantenna to allow the microwave energy to be spread over an extendedsurface. However, such systems are complicated, require specificgeometry, and are limited in the power density that can be coupled tothe plasma.

Furthermore, microwave sources typically generate plasmas that are nothighly uniform and/or are not able to have a spatially tunable density.Particularly, the uniformity of the plasma source is dependent on themodes of the standing wave pattern of the microwave with respect to theparticular geometry of the microwave cavity or antenna. Thus, theuniformity is determine mainly by the geometry of the design and is nottunable. As the substrates that are being processed continue to increasein size, it becomes increasingly difficult to account for edge effectsdue to the inability to tune the plasma. Additionally, the inability totune the plasma limits the ability to modify processing recipes toaccount for incoming substrate nonuniformity and adjust the plasmadensity for processing systems in which a nonuniformity is required tocompensate for the design of the processing system (e.g., to accommodatethe nonuniform radial velocity of the rotating wafers in some processingchambers).

SUMMARY

Embodiments include a plasma processing tool that includes a processingchamber, and a plurality of modular microwave sources coupled to theprocessing chamber. In an embodiment, the plurality of modular microwavesources include an array of applicators that are positioned over adielectric body that forms a portion of an outer wall of the processingchamber. The array of applicators may be coupled to the dielectric body.Additionally, the plurality of modular microwave sources may include anarray of microwave amplification modules. In an embodiment, eachmicrowave amplification module may be coupled to at least one of theapplicators in the array of applicators.

According to an embodiment, the dielectric body be planar or non-planar.In an embodiment, the dielectric body may by symmetric or non-symmetric.In yet another embodiment, the dielectric body may include a pluralityof recesses. In such an embodiment, at least one applicator may bepositioned in at least one of the recesses.

In an additional embodiment, the applicators may include a dielectricresonant cavity, an applicator housing formed around an outer sidewallof the dielectric resonant cavity, a monopole extending down an axialcenter of the dielectric resonator and into a channel formed in thecenter of the dielectric resonant cavity. Embodiments may also includemicrowave amplification modules that include a pre-amplifier, a mainpower amplifier, a power supply electrically coupled to thepre-amplifier, and the main power amplifier, and a circulator.

The above summary does not include an exhaustive list of allembodiments. It is contemplated that all systems and methods areincluded that can be practiced from all suitable combinations of thevarious embodiments summarized above, as well as those disclosed in theDetailed Description below and particularly pointed out in the claimsfiled with the application. Such combinations have particular advantagesnot specifically recited in the above summary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a plasma processing tool that includesa modular microwave plasma source, in accordance with an embodiment.

FIG. 2 is a schematic block diagram of a solid state microwave plasmasource, in accordance with an embodiment.

FIG. 3A is cross-sectional illustration of an applicator that may beused to couple microwave radiation to a processing chamber, inaccordance with an embodiment.

FIG. 3B is a cross-sectional illustration of an array of applicatorspositioned on a dielectric sheet that is part of the processing chamber,in accordance with an embodiment.

FIG. 4A is a plan view of an array of applicators that may be used tocouple microwave radiation to a processing chamber, in accordance withan embodiment.

FIG. 4B is a plan view of an array of applicators that may be used tocouple microwave radiation to a processing chamber, in accordance withan additional embodiment.

FIG. 4C is a plan view of an array of applicators and a plurality ofsensors for detecting conditions of a plasma, in accordance with anembodiment.

FIG. 4D is a plan view of an array of applicators that are formed in onezone of a multi-zone processing tool, in accordance with an embodiment.

FIG. 5A is a perspective view of an array of applicators mounted over asymmetric dielectric plate, according to an embodiment.

FIG. 5B is a perspective view cut-away of an array of applicators thatare partially embedded within a symmetric dielectric plate, according toan embodiment.

FIG. 5C is a perspective view of an array of applicators mounted over anirregular shaped dielectric plate, according to an embodiment.

FIG. 5D is a cross-sectional illustration of an array of applicatorspartially embedded within a non-planar dielectric body, according to anembodiment.

FIG. 5E is a cross-sectional illustration of an array of applicatorspartially embedded within a spherical dielectric body, according to anembodiment.

FIG. 6 illustrates a block diagram of an exemplary computer system thatmay be used in conjunction with a modular microwave radiation source, inaccordance with an embodiment.

DETAILED DESCRIPTION

Devices that include one or more modular microwave plasma sources aredescribed in accordance with various embodiments. In the followingdescription, numerous specific details are set forth in order to providea thorough understanding of embodiments. It will be apparent to oneskilled in the art that embodiments may be practiced without thesespecific details. In other instances, well-known aspects are notdescribed in detail in order to not unnecessarily obscure embodiments.Furthermore, it is to be understood that the various embodiments shownin the accompanying drawings are illustrative representations and arenot necessarily drawn to scale.

Embodiments include a microwave source that comprises one or moremicrowave modules. According to an embodiment, each microwave modulecomprises a microwave solid state electronics portion and an applicatorportion. In an embodiment, the applicator portion may be a dielectricresonator.

The use of solid state electronics instead of a magnetron allows for asignificant reduction in the size and the complexity of the plasmasource. Particularly, the solid state components are much smaller thanthe magnetron hardware described above. Additionally, the use of adistributed arrangement employing solid state components allows for theelimination of bulky waveguides needed to transmit the microwaveradiation to the processing chamber. Instead, the microwave radiationmay be transmitted with coaxial cabling. The elimination of waveguidesalso allows for the construction of a large area microwave source wherethe size of the plasma formed is not limited by the size of waveguides.Instead, an array of microwave modules may be constructed in a givenpattern that allows for the formation of a plasma that is arbitrarilylarge (and arbitrarily shaped) to match the shape of any substrate. Forexample, the applicators of the microwave modules may be arranged on (orpartially embedded within) dielectric bodies that are any desired shape,(e.g., symmetric plates, irregular plates, non-planar dielectric bodies,dielectric structures with internal voids, or the like). Furthermore,the cross-sectional shape of the applicators may be chosen so that thearray of applicators may be packed together as tightly as possible(i.e., a closed-packed array). Embodiments may also allow forapplicators in the array of microwave modules to have non-uniform sizes.As such, the packing efficiency may be improved further.

The use of an array of microwave modules also provides greaterflexibility in the ability to locally change the plasma density byindependently changing the power settings of each microwave module. Thisallows for uniformity optimization during plasma processing, such asadjustments made for wafer edge effects, adjustments made for incomingwafer nonuniformity, and the ability to adjust the plasma density forprocessing systems in which a nonuniformity is needed to compensate forthe design of the processing system (e.g., to accommodate the nonuniformradial velocity of the rotating wafers in some processing chambers).

Additional embodiments may also include one or more plasma monitoringsensors. Such embodiments provide a way to measure the density of theplasma (or any other plasma property) locally by each applicator, and touse that measurement as part of a feedback loop to control the powerapplied to each microwave module. Accordingly, each microwave module mayhave independent feedback, or a subset of the microwave modules in thearray may be grouped in zones of control where the feedback loopcontrols the subset of microwave modules in the zone.

In addition to the enhanced tuneability of the plasma, the use ofindividual microwave modules provides a greater power density thancurrently available plasma sources. For example, microwave modules mayallow for a power density that is approximately five or more timesgreater than typical RF plasma processing systems. For example, typicalpower into a plasma enhanced chemical vapor deposition process isapproximately 3,000 W, and provides a power density of approximately 4W/cm² for a 300 mm diameter wafer. In contrast, microwave modulesaccording to embodiments may use a 300 W power amplifier with a 4 cmdiameter applicator, to provide a power density of approximately 24W/cm².

Referring now to FIG. 1, a cross-sectional illustration of a processingtool 100 is shown, according to an embodiment. The processing tool 100may be a processing tool suitable for any type of processing operationthat utilizes a plasma. For example, the plasma processing tool 100 maybe a processing tool used for plasma enhanced chemical vapor deposition(PECVD), plasma enhanced atomic layer deposition (PEALD), etch andselective removal, and plasma cleaning. While the embodiments describedin detail herein are directed to plasma processing tools, it is to beappreciated that additional embodiments may include a processing tool100 that include any tool that utilizes microwave radiation. Forexample, a processing tool 100 that utilizes microwave radiation withoutneeding the formation of a plasma may include industrial heating and/orcuring processing tools 100.

Generally, embodiments include a processing tool 100 that includes achamber 178. In processing tools 178 that are used for plasmaprocessing, the chamber 178 may be a vacuum chamber. A vacuum chambermay include a pump (not shown) for removing gases from the chamber toprovide the desired vacuum. Additional embodiments may include a chamber178 that includes one or more gas lines 170 for providing processinggasses into the chamber 178 and exhaust lines 172 for removingbyproducts from the chamber 178. While not shown, it is to beappreciated that the processing tool may include a showerhead for evenlydistributing the processing gases over a substrate 174.

In an embodiment, the substrate 174 may be supported on a chuck 176. Forexample, the chuck 176 may be any suitable chuck, such as anelectrostatic chuck. The chuck may also include cooling lines and/or aheater to provide temperature control to the substrate 174 duringprocessing. Due to the modular configuration of the microwave modulesdescribed herein, embodiments allow for the processing tool 100 toaccommodate any sized substrate 174. For example, the substrate 174 maybe a semiconductor wafer (e.g., 200 mm, 300 mm, 450 mm, or larger).Alternative embodiments also include substrates 174 other thansemiconductor wafers. For example, embodiments may include a processingtool 100 configured for processing glass substrates, (e.g., for displaytechnologies).

According to an embodiment, the processing tool 100 includes one or moremodular microwave sources 105. The modular microwave source 105 mayinclude solid state microwave amplification circuitry 130 and anapplicator 142. In an embodiment, a voltage control circuit 110 providesan input voltage to a voltage controlled oscillator 120 in order toproduce microwave radiation at a desired frequency that is transmittedto the solid state microwave amplification circuitry 130 in each modularmicrowave source 105. After processing by the microwave amplificationcircuitry 130, the microwave radiation is transmitted to the applicator142. According to an embodiment, an array 140 of applicators 142 arecoupled to the chamber 178 and each function as an antenna for couplingthe microwave radiation to the processing gasses in the chamber 178 toproduce a plasma.

Referring now to FIG. 2, a schematic block diagram of the electronics ina modular microwave source is shown and described in greater detail,according to an embodiment. As described above, a voltage controlcircuit 110 provides an input voltage to a voltage controlled oscillator120. Embodiments may include an input voltage between approximately 1Vand 10V DC. The voltage controlled oscillator 120 is an electronicoscillator whose oscillation frequency is controlled by the inputvoltage. According to an embodiment, the input voltage from the voltagecontrol circuit 110 results in the voltage controlled oscillator 120oscillating at a desired frequency. In an embodiment, the microwaveradiation may have a frequency between approximately 2.3 GHz and 2.6GHz.

According to an embodiment, the microwave radiation is transmitted fromthe voltage controlled oscillator 120 to the microwave amplificationcircuitry 130. In the illustrated embodiment, a single instance of themicrowave amplification circuitry 130 is shown. However, embodiments mayinclude any number of instances of microwave amplification circuitry130. Particularly, the number of instances of microwave amplificationcircuitry 130 may be equal to the number of applicators 142 needed inthe array 140 of applicators 142. As such, each applicator 142 may becoupled to different instances of the microwave amplification circuitry130 to provide individual control of the power supplied to eachapplicator 142. According to an embodiment, when more than one modularmicrowave source 105 is used in the process tool 100, the microwaveamplification circuitry 130 may include a phase shifter 232. When only asingle applicator is used, the phase shifter 232 may be omitted. Themicrowave amplification circuitry 130 may also include adriver/pre-amplifier 234, and a main microwave power amplifier 236 thatare each coupled to a power supply 239. According to an embodiment, themicrowave amplification circuitry 130 may operate in a pulse mode. Forexample, the microwave amplification circuitry 130 may have a duty cyclebetween 1% and 99%. In a more particular embodiment, the microwaveamplification circuitry 130 may have a duty cycle between approximately15% and 30%.

In an embodiment, the microwave radiation may be transmitted to theapplicator 142 after being amplified. However, part of the powertransmitted to the applicator 142 may be reflected back due to themismatch in the output impedance. Accordingly, some embodiments alsoinclude a feedback line 286 that allows for the level of reflected powerto be fed back to the voltage control circuit 110. The level ofreflected power V_(feedback) may be directed to the feedback line 286 byusing a circulator 238 between the power amplifier 236 and theapplicator 142. The circulator 238 directs the reflected power to adummy load 282 and ground 284, with the level of reflected powerV_(feedback) being read prior to the dummy load 282. In an embodiment,the level of reflected power V_(feedback) may be used by the voltagecontrol circuit 110 to adjust the output voltage that is sent to thevoltage controlled oscillator 120, which in turn varies the outputfrequency of the microwave radiation that is transmitted to themicrowave amplification circuitry 130. The presence of such a feedbackloop allows for embodiments to provide continuous control of the inputvoltage of the voltage controlled oscillator 120, and allows forreductions in the level of reflected power V_(feedback). In anembodiment, the feedback control of the voltage controlled oscillator120 may allow for the level of the reflected power to be less thanapproximately 5% of the forward power. In some embodiments, the feedbackcontrol of the voltage controlled oscillator 120 may allow for the levelof the reflected power to be less than approximately 2% of the forwardpower. Accordingly, embodiments allow for an increased percentage of theforward power to be coupled into the processing chamber 178, andincreases the available power density coupled to the plasma.Furthermore, impedance tuning using a feedback line 286 is superior toimpedance tuning in typical slot-plate antennas. In slot-plate antennas,the impedance tuning involves moving two dielectric slugs formed in theapplicator. This involves mechanical motion of two separate componentsin the applicator, which increases the complexity of the applicator.Furthermore, the mechanical motion may not be as precise as the changein frequency that may be provided by a voltage controlled oscillator120.

Referring now to FIG. 3A, a cut-away illustration of an applicator 142is shown, according to an embodiment. In an embodiment, the microwaveradiation is transmitted to an applicator 142 by a coaxial cable 351that couples to a monopole 357 that extends axially through theapplicator 142. The monopole 357 may also extend into a channel 358formed into a center of a dielectric resonant cavity 353. The dielectricresonant cavity 353 may be a dielectric material, such as quartz,aluminum oxide, titanium oxide, or the like. Additional embodiments mayalso include a resonant cavity 353 that does not include a material(i.e., the dielectric resonant cavity 353 may be air or a vacuum).According to an embodiment, the dielectric resonator is dimensioned sothat the dielectric resonator supports resonance of the microwaveradiation. Generally, the size of the dielectric resonant cavity 353 isdependent on the dielectric constant of the material used to form thedielectric resonant cavity 353 and the frequency of the microwaveradiation. For example, materials with higher dielectric constants wouldallow for smaller resonant cavities 353 to be formed. In an embodimentwhere the dielectric resonant cavity 353 includes a circularcross-section, the diameter of the dielectric resonant cavity 353 may bebetween approximately 1 cm and 15 cm. In an embodiment, thecross-section of the dielectric resonant cavity 353 along a planeperpendicular to the monopole 357 may be any shape, so long as thedielectric resonant cavity 353 is dimensioned to support resonance. Inthe illustrated embodiment, the cross-section along a planeperpendicular to the monopole 357 is circular, though other shapes mayalso be used, such as polygons (e.g., triangles, rectangles, etc.),symmetrical polygons (e.g., squares, pentagons, hexagons, etc.),ellipses, or the like).

In an embodiment, the cross-section of the dielectric resonant cavity353 may not be the same at all planes perpendicular to the monopole 357.For example, the cross-section of a bottom extension proximate to theopen end of the applicator housing 355 is wider than the cross-sectionof the dielectric resonant cavity proximate to the channel 358. Inaddition to having cross-sections of different dimensions, thedielectric resonant cavity 353 may have cross-sections with differentshapes. For example, the portion of the dielectric resonant cavity 353proximate to the channel 358 may have a circular shaped cross-section,whereas the portion of the dielectric resonant cavity 353 proximate tothe open end of the applicator housing 355 may be a symmetrical polygonshape (e.g., pentagon, hexagon, etc.). However, it is to be appreciatedthat embodiments may also include a dielectric resonant cavity 353 thathas a uniform cross-section at all planes perpendicular to the monopole357.

According to an embodiment, the applicator 353 may also include animpedance tuning backshort 356. The backshort 356 may be a displaceableenclosure that slides over an outer surface of the applicator housing355. When adjustments to the impedance need to be made, an actuator (notshown) may slide the backshort 356 along the outer surface of theapplicator housing 355 to change a distance D between a surface of thebackshort 356 and a top surface of the dielectric resonant cavity 353.As such, embodiments provide more than one way to adjust the impedancein the system. According to an embodiment, an impedance tuning backshort356 may be used in conjunction with the feedback process described aboveto account for impedance mismatches. Alternatively, the feedback processor an impedance tuning backshort 356 may be used by themselves to adjustfor impedance mismatches.

According to an embodiment, the applicator 142 functions as a dielectricantenna that directly couples the microwave electromagnetic field intothe processing chamber 178. The particular axial arrangement of themonopole 357 entering the dielectric resonant cavity 353 may produce anTM01δ mode excitation. However different modes of excitation may bepossible with different applicator arrangements. For example, while anaxial arrangement is illustrated in FIG. 3, it is to be appreciated thatthe monopole 357 may enter the dielectric resonant cavity 353 from otherorientations. In one such embodiment, the monopole 357 may enter thedielectric resonant cavity 353 laterally, (i.e., through a sidewall ofthe dielectric resonant cavity 353).

Referring now to FIG. 3B, an illustration of a portion of a processingtool 100 with an array 140 of applicators 142 coupled to the chamber 178is shown, according to an embodiment. In the illustrated embodiment, themicrowave radiation from the applicators 142 is coupled into the chamber178 by being positioned proximate to a dielectric plate 350. Theproximity of the applicators 142 to the dielectric plate 350 allows forthe microwave radiation resonating in the dielectric resonant cavity 353(not shown in FIG. 3B) to couple with the dielectric plate 350, whichmay then couple with processing gasses in the chamber to generate aplasma. In one embodiment, the dielectric resonant cavity 353 may be indirect contact with the dielectric plate 350. In an additionalembodiment, the dielectric resonant cavity 353 may be spaced away from asurface of the dielectric plate 350, so long as the microwave radiationcan still be transferred to the dielectric plate 350.

According to an embodiment, the array 140 of applicators 142 may beremovable from the dielectric plate 350 (e.g., for maintenance, torearrange the array of applicators to accommodate a substrate withdifferent dimensions, or for any other reason) without needing to removethe dielectric plate 350 from the chamber 178. Accordingly, theapplicators 142 may be removed from the processing tool 100 withoutneeding to release a vacuum in the chamber 178. According to anadditional embodiment, the dielectric plate 350 may also function as agas injection plate or a showerhead.

As noted above, an array of applicators 140 may be arranged so that theyprovide coverage of an arbitrarily shaped substrate 174. FIG. 4A is aplan view illustration of an array 140 of applicators 142 that arearranged in a pattern that matches a circular substrate 174. By forminga plurality of applicators 142 in a pattern that roughly matches theshape of the substrate 174, the plasma becomes tunable over the entiresurface of the substrate 174. For example, each of the applicators 142may be controlled so that a plasma with a uniform plasma density acrossthe entire surface of the substrate 174 is formed. Alternatively, one ormore of the applicators 142 may be independently controlled to provideplasma densities that are variable across the surface of the substrate174. As such, incoming nonuniformity present on the substrate may becorrected. For example, the applicators 142 proximate to an outerperimeter of the substrate 174 may be controlled to have a differentpower density than applicators proximate to the center of the substrate174.

In FIG. 4A, the applicators 142 in the array 140 are packed together ina series of concentric rings that extend out from the center of thesubstrate 174. However, embodiments are not limited to suchconfigurations, and any suitable spacing and/or pattern may be useddepending on the needs of the processing tool 100. Furthermore,embodiments allow for applicators 142 with any symmetricalcross-section, as described above. Accordingly, the cross-sectionalshape chosen for the applicator may be chosen to provide enhancedpacking efficiency.

Referring now to FIG. 4B, a plan view of an array 140 of applicators 142with a non-circular cross-section is shown, according to an embodiment.The illustrated embodiment includes applicators 142 that have hexagonalcross-sections. The use of such an applicator may allow for improvedpacking efficiency because the perimeter of each applicator 142 may matenearly perfectly with neighboring applicators 142. Accordingly, theuniformity of the plasma may be enhanced even further since the spacingbetween each of the applicators 142 may be minimized. While FIG. 4Billustrates neighboring applicators 142 sharing sidewall surfaces, it isto be appreciated that embodiments may also include non-circularsymmetrically shaped applicators that include spacing betweenneighboring applicators 142.

Referring now to FIG. 4C, an additional plan-view illustration of anarray 140 of applicators 142 is shown according to an embodiment. Thearray 140 in FIG. 4C is substantially similar to the array 140 describedabove with respect to FIG. 4A, except that a plurality of sensors 490are also included. The plurality of sensors provides improved processmonitoring capabilities that may be used to provide additional feedbackcontrol of each of the modular microwave sources 105. In an embodiment,the sensors 490 may include one or more different sensor types 490, suchas plasma density sensors, plasma emission sensors, or the like.Positioning the sensors across the surface of the substrate 174 allowsfor the plasma properties at given locations of the processing chamber100 to be monitored.

According to an embodiment, every applicator 142 may be paired with adifferent sensor 490. In such embodiments, the output from each sensor490 may be used to provide feedback control for the respectiveapplicator 142 to which the sensor 490 has been paired. Additionalembodiments may include pairing each sensor 490 with a plurality ofapplicators 142. For example, each sensor 490 may provide feedbackcontrol for multiple applicators 142 to which the sensor 490 isproximately located. In yet another embodiment, feedback from theplurality of sensors 490 may be used as a part of a multi-inputmulti-output (MIMO) control system. In such an embodiment, eachapplicator 142 may be adjusted based on feedback from multiple sensors490. For example, a first sensor 490 that is a direct neighbor to afirst applicator 142 may be weighted to provide a control effort to thefirst applicator 142 that is greater than the control effort exerted onthe first applicator 142 by a second sensor 490 that is located furtherfrom the first applicator 142 than the first sensor 490.

Referring now to FIG. 4D, an additional plan-view illustration of anarray 140 of applicators 142 positioned in a multi-zone processing tool100 is shown, according to an embodiment. In an embodiment, themulti-zone processing tool 100 may include any number of zones. Forexample, the illustrated embodiment includes zones 475 ₁-475 _(n). Eachzone 475 may be configured to perform different processing operations onsubstrates 174 that are rotated through the different zones 475. Asillustrated, a single array 140 is positioned in zone 475 _(n). However,embodiments may include multi-zone processing tools 100 with an array140 of applicators 142 in one or more of the different zones 475,depending on the needs of the device. The spatially tunable density ofthe plasma provided by embodiments allows for the accommodation ofnonuniform radial velocity of the rotating substrates 174 as they passthrough the different zones 475.

Referring now to FIGS. 5A-5E, different embodiments are shown thatillustrate the flexible nature of how the array of applicators 140 maybe arranged in order provide various shapes of plasma. As will bedescribed in greater detail below, embodiments allow for the applicators142 of the microwave modules to be arranged on (or partially embeddedwithin) dielectric bodies that are any desired shape, (e.g., symmetricplates, irregular plates, non-planar dielectric bodies, dielectricstructures with internal voids, or the like). Accordingly, embodimentsallow for plasmas to be generated that can be any desired shape and arenot limited to the constraining dimensions of waveguides, such as thoseused in currently available processing tools described above.

Referring now to FIG. 5A, a perspective view of an array 140 ofapplicators 142 positioned over a symmetric dielectric plate 550 isshown, according to an embodiment. In the illustrated embodiment, thedielectric plate 550 is substantially wedge shaped and is symmetricabout line 1-1′. According to an embodiment, the dielectric plate 550may function substantially the same as dielectric plate 350 describedabove with respect to FIG. 3B. As such, the microwave radiationresonating in the dielectric resonant cavity (not shown in FIG. 5A)couples with the dielectric plate 550, which may then couple withprocessing gasses in the chamber to generate a plasma. The dielectricplate 550 serves to spread the microwave radiation, and generally allowsfor the shape of the resulting plasma to substantially match the shapeof the dielectric plate 550, even though the microwave radiationoriginates from a plurality of discrete applicators 142.

However, it is to be appreciated that the shape of the resulting plasmasis not limited by the shape of the dielectric plate 550 because each ofthe applicators 142 in the array 140 may be individually controllable orcontrolled in groups. As such, embodiments may allow for theconstructive and destructive interference of adjacent sources locallyand independently to achieve a desired plasma shape and/or to increaseuniformity of the plasma. For example, the microwave sources forneighboring applicators 142 may be phase locked to each other with acertain phase differences to produce a desired plasma shape. In aparticular embodiment, two adjacent applicators 142 may have theirmicrowave sources phase locked to 180 degree out of phase. This willresult in a destructive interference of the two microwave sourcesbetween the applicators resulting in a weaker plasma density in thatlocation. Similarly, constructive interference may be used to produce astronger plasma density in a desired location.

Additionally, controlling frequency, amplitude, phase angle, and dutycycle during a time period for each of the applicators 142 (or groups ofapplicators 142) may be used to improve uniformity of the on-waferresult. The individualized control of any or all of these parameters foreach of the applicators 142 allows for “hot spots” due to interactionsof the applicators 142 to be minimized or avoided completely. In anembodiment, varying the frequency and amplitude of the power sources tothe individual applicators 142 results in improved uniformity becausethe hot spots are reduced and/or time-averaged. In an embodiment, thetiming of the pulsed power to each module is varied to minimizeinteractions, for example by having nearest neighbors where the timingof the pulsed power is such that no neighboring applicators 142 are bothon at the same time.

In an embodiment, the thickness of the dielectric plate 550 is minimizedin order to place the applicators 142 as close to the processingenvironment as possible. For example, the thickness of the dielectricplate 550 may be less than approximately 30 mm. In some embodiments, thethickness of the dielectric plate 550 may be between 5 mm and 15 mmthick. However, it is to be appreciated that decreasing the thickness ofthe dielectric plate 550 may reduce the structural integrity of thedielectric plate 550. Depending on the conditions in the processingchamber, reducing the thickness of the dielectric plate 550 may resultin the pressure external to the processing chamber cracking or otherwisedamaging the dielectric plate 550.

Accordingly, embodiments may also include a dielectric plate thatincludes recesses in which the applicators may be placed. A dielectricplate according to such an embodiment is illustrated in FIG. 5B. In theillustrated embodiment, six recesses 552 are formed into the dielectricplate 550. However, it is to be appreciated that an number of recesses552 may be included. For illustrative purposes, two of the recesses 552are empty (i.e., there is no applicator 142 placed in the recess 552) inorder to show an exemplary illustration of how a recess 552 may lookwithout an applicator 142. Additionally, it is to be appreciated that insome embodiments the applicators 142 may be seated into the recess 552,but not permanently affixed to the dielectric plate 550. Accordingly,the applicators 142 may be removed as needed.

The recesses 552 allow for the applicators 142 to be separated from theprocessing area of the chamber by a thinner portion of the dielectricmaterial. Accordingly, the transfer of the microwave radiation into theprocessing chamber may be more efficient without significantly reducingthe structural integrity of the dielectric plate 550. For example, inembodiments with a recesses 552, the applicators 142 may be separatedfrom the processing area of the chamber by a dielectric material with athickness less than 15 mm. In some embodiments, the thickness of thedielectric material at the bottom of the recess 552 may be approximately5 mm or less.

In addition to illustrating the recesses 552, FIG. 5B also illustratesthat embodiments may also include applicators 142 that are not all thesame size. For example, the recesses 552 that are empty (i.e., the twoleftmost recesses 552) are smaller than the other recesses 552. As such,the applicators 142 that are designed to fit into these recesses mayhave a smaller diameter cross-section than the other applicators 142.The size of the applicators 142 may be varied without changing theresonance by changing the dielectric material in the applicator 142. Forexample the dielectric constant of the resonator in each applicator 142may be chosen so that each applicator 142 has the same resonance. Theability to modify the size of the applicators 142 allows for increasedpacking efficiency over the dielectric plate 550. For example, in thewedge shaped dielectric plate 550 illustrated in FIG. 5B, the smallerapplicators 142 may be positioned along the narrower portion of thewedge in order to ensure applicators 142 are positioned over a greaterportion of the surface area of the dielectric plate 550.

As noted above, the modular design and tunability of the array 140 ofapplicators 142 allows for the formation of a plasma of any desiredshape. A generic example of such an embodiment is illustrated in theperspective view shown in FIG. 5C. As illustrated, the dielectric plate550 in FIG. 5C is an arbitrary shape and a plurality of applicators 142are placed over the surface of the dielectric plate 550. In otherembodiments, the dielectric plate 550 may be any shape, (e.g., polygon,circular, elliptical, the shape may include straight edges and curvededges, or the like). In such embodiments, the applicators 142 may bedistributed over the surface in order to provide the desired shape ofthe plasma. For example, the applicators 142 may each be a uniformshape, the applicators 142 may include multiple different shapes, theremay be applicators 142 with different geometries, or the any otherconfiguration needed to provide the desired shape of the plasma.Furthermore, while the applicators 142 illustrated in FIG. 5C are shownsitting on a top surface of the dielectric plate 550, it is to beappreciated that the applicators 142 may also be placed in recessesformed in the dielectric plate 550, similar to FIG. 5B described above.

In yet another embodiment, the array of applicators may be arranged in anon-planar configuration. Such an embodiment is illustrated in thecross-sectional illustration shown in FIG. 5D. As shown in FIG. 5D, anarray 140 of applicators 142 are set into recess 552 formed into anon-planar dielectric body 550. In the illustrated embodiment, thenon-planar dielectric body 550 is shown in the X-Z plane. In anembodiment, the non-planar dielectric body 550 may be any shape thatallows for the applicators 142 to be positioned at a non-uniformZ-height. For example, the non-planar dielectric body 550 may be archshaped, dome shaped, pyramid shaped, sphere shaped, or any other desiredshaped. Accordingly, embodiments allow for the formation of asubstantially non-planar plasma within a processing chamber. Such anembodiment may be beneficial when a plasma process is needed to processobjects that are not necessarily planar (e.g., objects other thansubstrates, such as wafers, plates, or the like), or collections ofobjects that are arrayed in a non-planar group.

According to another embodiment, a non-planar dielectric body 550 mayhave a cross-section which is circular. Such an embodiment is shown inthe cross-sectional illustration shown in FIG. 5E. As shown, thenon-planar dielectric body 550 forms a ring in the X-Z plane. In someembodiments, the non-planar dielectric body 550 may extend in the Yplane to form a cylinder. In a further embodiment, a non-planardielectric body may have cross-section which is triangular. In a furtherembodiment, a non-planar dielectric body may have cross-section which issquare. In a further embodiment, a non-planar dielectric body may havecross-section which is rectangular. In a further embodiment, anon-planar dielectric body may have cross-section for which the boundaryis a Jordan curve (i.e. a non-self-intersecting continuous loop in aplane). In additional embodiments the non-planar dielectric body 550 mayform a sphere (i.e., the non-planar dielectric body may be a dielectricbody with an internal void). In embodiments where the non-planardielectric body 550 is a three-dimensional shape with an internal void,the non-planar body 550 may be comprised of two or more dielectricbodies that are coupled together to form the shape. Such embodiments maybe beneficial when a plasma process is needed to process all surfaces ofa three-dimensional object.

Referring now to FIG. 6, a block diagram of an exemplary computer system660 of a processing tool 100 is illustrated in accordance with anembodiment. In an embodiment, computer system 660 is coupled to andcontrols processing in the processing tool 100. Computer system 660 maybe connected (e.g., networked) to other machines in a Local Area Network(LAN), an intranet, an extranet, or the Internet. Computer system 660may operate in the capacity of a server or a client machine in aclient-server network environment, or as a peer machine in apeer-to-peer (or distributed) network environment. Computer system 660may be a personal computer (PC), a tablet PC, a set-top box (STB), aPersonal Digital Assistant (PDA), a cellular telephone, a web appliance,a server, a network router, switch or bridge, or any machine capable ofexecuting a set of instructions (sequential or otherwise) that specifyactions to be taken by that machine. Further, while only a singlemachine is illustrated for computer system 660, the term “machine” shallalso be taken to include any collection of machines (e.g., computers)that individually or jointly execute a set (or multiple sets) ofinstructions to perform any one or more of the methodologies describedherein.

Computer system 660 may include a computer program product, or software622, having a non-transitory machine-readable medium having storedthereon instructions, which may be used to program computer system 660(or other electronic devices) to perform a process according toembodiments. A machine-readable medium includes any mechanism forstoring or transmitting information in a form readable by a machine(e.g., a computer). For example, a machine-readable (e.g.,computer-readable) medium includes a machine (e.g., a computer) readablestorage medium (e.g., read only memory (“ROM”), random access memory(“RAM”), magnetic disk storage media, optical storage media, flashmemory devices, etc.), a machine (e.g., computer) readable transmissionmedium (electrical, optical, acoustical or other form of propagatedsignals (e.g., infrared signals, digital signals, etc.)), etc.

In an embodiment, computer system 660 includes a system processor 602, amain memory 604 (e.g., read-only memory (ROM), flash memory, dynamicrandom access memory (DRAM) such as synchronous DRAM (SDRAM) or RambusDRAM (RDRAM), etc.), a static memory 606 (e.g., flash memory, staticrandom access memory (SRAM), etc.), and a secondary memory 618 (e.g., adata storage device), which communicate with each other via a bus 630.

System processor 602 represents one or more general-purpose processingdevices such as a microsystem processor, central processing unit, or thelike. More particularly, the system processor may be a complexinstruction set computing (CISC) microsystem processor, reducedinstruction set computing (RISC) microsystem processor, very longinstruction word (VLIW) microsystem processor, a system processorimplementing other instruction sets, or system processors implementing acombination of instruction sets. System processor 602 may also be one ormore special-purpose processing devices such as an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA), adigital signal system processor (DSP), network system processor, or thelike. System processor 602 is configured to execute the processing logic626 for performing the operations described herein.

The computer system 660 may further include a system network interfacedevice 608 for communicating with other devices or machines. Thecomputer system 660 may also include a video display unit 610 (e.g., aliquid crystal display (LCD), a light emitting diode display (LED), or acathode ray tube (CRT)), an alphanumeric input device 612 (e.g., akeyboard), a cursor control device 614 (e.g., a mouse), and a signalgeneration device 616 (e.g., a speaker).

The secondary memory 618 may include a machine-accessible storage medium631 (or more specifically a computer-readable storage medium) on whichis stored one or more sets of instructions (e.g., software 622)embodying any one or more of the methodologies or functions describedherein. The software 622 may also reside, completely or at leastpartially, within the main memory 604 and/or within the system processor602 during execution thereof by the computer system 660, the main memory604 and the system processor 602 also constituting machine-readablestorage media. The software 622 may further be transmitted or receivedover a network 620 via the system network interface device 608.

While the machine-accessible storage medium 631 is shown in an exemplaryembodiment to be a single medium, the term “machine-readable storagemedium” should be taken to include a single medium or multiple media(e.g., a centralized or distributed database, and/or associated cachesand servers) that store the one or more sets of instructions. The term“machine-readable storage medium” shall also be taken to include anymedium that is capable of storing or encoding a set of instructions forexecution by the machine and that cause the machine to perform any oneor more of the methodologies. The term “machine-readable storage medium”shall accordingly be taken to include, but not be limited to,solid-state memories, and optical and magnetic media.

In the foregoing specification, specific exemplary embodiments have beendescribed. It will be evident that various modifications may be madethereto without departing from the scope of the following claims. Thespecification and drawings are, accordingly, to be regarded in anillustrative sense rather than a restrictive sense.

What is claimed is:
 1. A plasma processing tool, comprising: aprocessing chamber; and a plurality of modular microwave sources coupledto the processing chamber, wherein the plurality of modular microwavesources comprise: an array of applicators, wherein the array ofapplicators are positioned over a dielectric body that forms a portionof an outer wall of the processing chamber, and wherein each applicatorcomprises a dielectric resonant cavity, wherein the dielectric resonantcavity is a solid material, an applicator housing around an outersidewall of the dielectric resonant cavity, and a monopole extendingdown an axial center of the dielectric resonant cavity and into achannel formed in the center of the dielectric resonant cavity whereinan end of the monopole antenna is spaced away from a bottom surface ofthe channel, and wherein the array of applicators are coupled to thedielectric body; and an array of microwave amplification modules,wherein each microwave amplification module comprises a main amplifier,and is coupled to at least one of the applicators in the array ofapplicators, wherein the dielectric body comprises a plurality ofrecesses, wherein at least one applicator is within at least one of therecesses, and wherein at least a portion of the applicator housing, aportion of the dielectric resonant cavity, and a portion of the monopoleare positioned within the recess, and wherein the plurality of recessesdo not pass entirely through the dielectric body.
 2. The plasmaprocessing tool of claim 1, wherein the dielectric body is symmetrical.3. The plasma processing tool of claim 2, wherein the dielectric body issubstantially wedge shaped.
 4. The plasma processing tool of claim 1,wherein the dielectric body is non-symmetrical.
 5. The plasma processingtool of claim 1, wherein the dielectric body is non-planar.
 6. Theplasma processing tool of claim 5, wherein the dielectric body is adome.
 7. The plasma processing tool of claim 6, wherein the array ofapplicators includes applicators with non-uniform dimensions.
 8. Theplasma processing tool of claim 7, wherein the resonance of each of theapplicators are uniform.
 9. The plasma processing tool of claim 6,wherein each of the microwave amplification modules are independentlycontrollable.
 10. The plasma processing tool of claim 6, furthercomprising a plurality of plasma sensors positioned among theapplicators.
 11. The plasma processing tool of claim 10, whereinfeedback control data for each microwave amplification module isprovided by one or more of the plurality of plasma sensors.
 12. A plasmaprocessing tool, comprising: a processing chamber, wherein at least onesurface of the processing chamber is a dielectric body wherein thedielectric body comprises a plurality of recesses; and a plurality ofmodular microwave sources coupled to the processing chamber, wherein theplurality of modular microwave sources comprise: an array ofapplicators, wherein the array of applicators are positioned in contactwith the dielectric body, and wherein each applicator comprises: adielectric resonant cavity, wherein the dielectric resonant cavity is asolid material; an applicator housing formed around an outer sidewall ofthe dielectric resonant cavity; a monopole extending down an axialcenter of the dielectric resonant cavity and into a channel formed inthe center of the dielectric resonant cavity, wherein an end of themonopole antenna is spaced away from a bottom surface of the channel;wherein at least a portion of the applicator housing, a portion of thedielectric resonant cavity, and a portion of the monopole are positionedwithin the recess, and wherein the plurality of recesses do not passentirely through the dielectric body; and an array of microwaveamplification modules, wherein each microwave amplification module iscoupled to at least one of the applicators in the array of applicators,and wherein each microwave amplification module comprises: apre-amplifier; a main power amplifier; a power supply electricallycoupled to the pre-amplifier, and the main power amplifier; and acirculator.
 13. The plasma processing tool of claim 12, wherein thedielectric body has a thickness that is less than approximately 30 mm.14. The plasma processing tool of claim 12, wherein the plurality ofrecesses are not the same size.
 15. The plasma processing tool of claim12, wherein the dielectric body is symmetric.
 16. The plasma processingtool of claim 12, wherein the dielectric body is non-planar.